1. Technical Field
This invention relates generally to low-cost, portable, hand-operated liquid pumps, such as hand-operated bilge pumps which are commonly employed to remove a body of collected water from a sump, small vessel or hole, and more particularly to improved field-repairable, light-weight, robust versions of such portable hand-operated liquid pumps.
2. Discussion
Manually-operated liquid hand pumps such as bilge and sump pumps are commonly employed to remove or pump collected liquid, such as water, from a given spot. For example, a hand pump user may easily pump out water that has collected in the bottom of a boat (i.e., bilge) or a sump in the lower portions of a building. For landscaping, irrigation installation, and construction applications, a portable hand pump may be conveniently used to remove water that has collected in foundation trenches, ditches, valve boxes, meter boxes, or holes at an excavation site. These and a wide variety of other applications may be easily accomplished with the use of a portable hand pump to avoid having to bail such liquids with a bucket, or employ other less convenient approaches, such as an electrically-operated hand pump.
A variety of manually-operated hand pumps have been developed and are commercially available. The conventional liquid hand pump generally includes a plunger mechanism which has a flexible seal which slidingly engages the smooth inner wall or bore of a tubular housing. The typical hand pump also has an inlet port and a check valve assembly located at the bottom end of the housing, and an outlet port located near the top end. The plunger mechanism is forcibly displaced through an up and down motion, i.e., reciprocal movement, within the housing by a push rod with handle that is operated by back-and-forth arm movements of a user. The plunger mechanism sealingly engages the inner walls of the tubular cylinder on the upstroke. This generally causes liquids that have collected above the plunger to be pumped out the outlet port. It further creates a partial vacuum below the plunger which sucks in more liquid through the inlet port. On the downstroke, the liquid held in the bore of the housing cannot escape through the inlet port because of the check valve. Thus, it is forced to flow past the pliant outer edge of the flexible seal as the plunger moves toward the bottom of the housing.
While prior art pumps of the manually operable type are widely used, many of the existing liquid hand pumps are designed, manufactured and sold as disposable units with pumping components which are permanently sealed together. However, hand-operated liquid pumps are generally known to be susceptible to mechanical failures, especially when pumping liquids containing mud, sand and other particulate. Because the prior art pump units are made up of components that are not easily accessible or replaceable, it is very difficult or impossible for a user to repair a component such as the plunger mechanism when repairs become necessary. Accordingly, the user is generally expected to replace the entire hand pump when failure occurs. This can be particularly bothersome to a user who would rather replace or repair an inexpensive component and be back in business within a few minutes with a serviceable pump, instead of having to leave the job site and make a trip to a store to purchase an entirely new pump at an added cost.
In addition, many of the prior art liquid hand pumps are designed to pump liquids out the exhaust or outlet port primarily during the upstroke of the plunger mechanism, and very little on the downstroke. Accordingly, the prior art pumps are not believed to provide for optimum pumping capacity in each direction. Such prior pumping approaches tend to ignore the ergonomics of reciprocal movement, and the amount of physical strength required by the user in each direction, especially for larger pumps where greater manual force is necessary to pump larger volumes of liquids.
Moreover, commercially available liquid hand pumps fail to accommodate the user who would like a versatile pump which can perform a variety of pumping operations. Adapters, connectors and removable fluid lines are not provided and thus the utility of the pump is greatly limited
It is therefore one object of the present invention to provide for an improved hand-operated liquid pump that is manufactured and assembled with inexpensive components that are easily connected together in a manner that enables a user to easily disassemble and repair the pump with a few simple hand tools when necessary.
It is a further object of the present invention is to provide a versatile hand pump kit that has a preselected group of interchangeable connectors, adapters, fittings, extenders, and accessories to choose from, which group easily enables a user to employ the pump under a variety of conditions, and for a variety of purposes or uses.
A still further object of the present invention is to provide for an improved hand pump that is capable of efficiently and ergonomically pumping liquid during both the upstroke movement and downstroke movement of the plunger mechanism.
One more object of the present invention is to provide for several improvements in the plunger mechanism that substantially sealingly engages the bore of the pump during the upstroke movements but yet requires reduced effort to operate in both stroke directions.
Yet another object of the present invention is to provide a manually-operable liquid hand pump which requires no glues for the assembly of the individual components to make the completed hand pump.
One more object of the present invention is to provide a repairable hand pump in order to reduce the amount of plastic or other pump components presently discarded into our society's waste stream when unrepairable pumps become unusable due to one or more damaged or worn components.
Finally, a further object of the present invention is to provide for a sturdy liquid hand pump that addresses the above-specified needs and yet is inexpensive, easy to use, to understand, and to repair to render the pump virtually good as new.